A radio frame in a Long Term Evolution (LTE) system and an LTE-Advanced (LTE-A) system adopts a frame structure of a Frequency Division Duplex (FDD) mode or a Time Division Duplex (TDD) mode. FIG. 1 is a schematic diagram of a frame structure in an existing LTE/LTE-A FDD system. As shown in FIG. 1, a 10 ms radio frame is composed of twenty slots which are 0.5 ms long and numbered from 0 to 19, and a slot 2i and a slot 2i+1 form a subframe i which is 1 ms long. FIG. 2 is a schematic diagram of a frame structure in an existing LTE/LTE-A TDD system. A 10 ms radio frame is composed of two half frames which are 5 ms long. Each half frame includes five subframes which are 1 ms long. A subframe i is defined as a slot 2i and a slot 2i+1 which are 0.5 ms long.
In above-mentioned two frame structures, for a Normal Cyclic Prefix (Normal CP), a time slot contains seven symbols which are 66.7 us long, wherein a CP length of a first symbol is 5.21 us, and CP lengths of the other six symbols are 4.69 us. For an Extended CP, a time slot contains six symbols, and CP lengths of all symbols are 16.67 us. Supported uplink-downlink configurations are shown in Table 1.
TABLE 1Downlink-Uplink-uplink downlinkconversion Subframe numberconfiguration point period012345678905msDSUUUDSUUU15msDSUUDDSUUD25msDSUDDDSUDD310msDSUUUDDDDD410msDSUUDDDDDD510msDSUDDDDDDD65msDSUUUDSUUD
As disclosed above, for each subframe in a radio frame, ‘D’ represents a subframe dedicated for downlink transmission, ‘U’ represents a subframe dedicated for uplink transmission, and ‘S’ represents a special subframe, containing a Downlink Pilot Time Slot (DwPTS), a Guard Period (GP) and an Uplink Pilot Time Slot (UpPTS).
In the LTE system, a Hybrid Automatic Repeat reQuest (HARQ) process refers to that: when data needs to be transmitted at a sending end, a receiving end allocates information needed during transmission via downlink signalling, such as frequency domain resources and packet information. The sending end sends the data according to these pieces of information, and saves the data in a cache of the sending end to facilitate retransmission. When receiving the data, the receiving end detects the data, if the data is correctly received, Acknowledged (ACK) information is sent to the sending end, after receiving the ACK information, the sending end empties the cache used in this transmission, and this transmission is ended. If the data is not correctly received, Non-acknowledged (NACK) information is sent to the sending end, packets which are not correctly received are saved in a cache of the receiving end. After receiving the NACK information, the sending end extracts the data from the cache of the sending end and retransmits the data at a corresponding subframe and a corresponding frequency domain position by using a specific packet format. After receiving retransmitted packets, the receiving end combines the retransmitted packets with packets which are not correctly received, detection is performed again; and then the process is repeated until the data are correctly received or a frequency of transmission of the data exceeds a maximum transmission frequency threshold.
In the LTE/LTE-A system, timing regulations regarding scheduling of a Physical Downlink Shared Channel (PDSCH) in a downlink HARQ, namely scheduling of the downlink HARQ, are as follows: an User Equipment (UE) detects a Physical Downlink Control Channel (PDCCH) on a subframe n, and analyzes a PDSCH of the current subframe according to information of the PDCCH.
In the LTE/LTE-A FDD system, timing rules regarding sending of a Physical Uplink Control Channel (PUCCH) corresponding to an HARQ-ACK of the PDSCH in the downlink HARQ are as follows, namely a timing relation of the downlink HARQ is regulated as follows: the UE detects the PDCCH for transmitting or indicating downlink Semi-Persistent Scheduling (SPS) release of the PDSCH on the subframe n, and transmits a corresponding HARQ-ACK response on a subframe n+4. In the LTE/LTE-A TDD system, a timing relation of the downlink HARQ is regulated as follows: the UE detects the PDCCH for transmitting or indicating the downlink SPS release of the PDSCH on a subframe n-k, and transmits a corresponding HARQ-ACK response on an uplink subframe n, where k belongs to K, and K is valued as shown in Table 2.
TABLE 2Value of K in Different Uplink-Downlink ConfigurationsUplink-downlinkSubframe number nconfiguration01234567890——6—4——6—41——7, 64———7, 64—2——8, 7, 4, 6————8, 7, 4, 6 ——3——7, 6, 116, 55, 4—————4——12, 8, 6, 5,——————7, 114, 75——13, 12, ———————9, 8, 7, 5, 4, 11, 66——775——77—
In the LTE system, in a FDD system, due to a one-to-one correspondence relation between uplink and downlink subframes, when the PDSCH contains only one transmission block, the UE needs to feed back 1-bit ACK/NACK answer information, and when the PDSCH contains two transmission blocks, the UE needs to feed back 2-bit ACK/NACK answer information. The UE sends ½-bit ACK/NACK answer information by using a PUCCH format1a/1b. In a TDD system, due to no existence of the one-to-one correspondence relation between the uplink and downlink subframes, that is, ACK/NACK answer information corresponding to a plurality of downlink subframes needs to be sent on a PUCCH of an uplink subframe, a downlink subframe set corresponding to the uplink subframe forms a ‘bundling window’. There are two sending methods for the ACK/NACK answer information. One sending method is a bundling method, of which a core concept refers to that: spatial bundling operation needs to be performed on the ACK/NACK answer information of at least one transmission block corresponding to each downlink subframe fed back by the uplink subframe, if a downlink subframe has two transmission blocks, the UE needs to feed back the 2-bit ACK/NACK answer information, if each subframe has only one transmission block, the UE needs to feed back the 1-bit ACK/NACK answer information, and the UE sends the ½-bit ACK/NACK answer information by using the PUCCH format1a/1b. Another sending method is a multiplexing (multiplexing with channel selection) method of which a core concept refers to that: different feedback states of downlink subframes needing to be fed back on the uplink subframe are represented by utilizing different PUCCHs and different modulation symbols on each of different PUCCHs, if each downlink subframe has a plurality of transmission blocks, spatial bundling and channel selection are successively performed on ACK/NACK fed back by the transmission blocks of each downlink subframe, and the UE sends an ACK/NACK answer message by using a format 1b with channel selection.
The most significant characteristics of the LTE-A system with respect to the LTE system refer to that: a carrier aggregation technology is introduced to the LTE-A system, that is, bandwidths of the LTE system are aggregated to obtain a larger bandwidth. In a system to which carrier aggregation is introduced, a carrier for aggregation is called a Component Carrier (CC), and is also called a serving cell. Meanwhile, concepts of a Primary Component Carrier/Cell (PCC/PCell) and a Secondary Component Carrier/Cell (SCC/SCell) are also proposed. In a carrier aggregated system, a primary serving cell and a secondary serving cell are included at least, wherein the primary serving cell is under an activated state all the time, and it is regulated that the PUCCH is transmitted only on the PCell.
An existing carrier aggregation technology is only applied to an FDD serving cell or a TDD serving cell. In a subsequent version, the FDD serving cell and the TDD serving cell are considered. When the FDD serving cell and the TDD serving cell are aggregated, if cross-carrier scheduling is enabled, when the TDD serving cell is the primary serving cell, only some downlink subframes are scheduled on the FDD serving cell. As shown in FIG. 3, when the primary serving cell is TDD uplink-downlink configuration #0 and the cross-carrier scheduling is enabled, only downlink subframes #0, #1, #5 and #6 on the FDD serving cell can be scheduled, so as to cause reduction of a downlink throughput. In order to ensure the downlink throughput, it is necessary to solve a problem that some downlink subframes on a scheduled serving cell cannot be scheduled. In addition, the existing LTE system adopts the same management mode including a scheduling mode, a transmission mode, a sequence generation mode, a scrambling mode, signal configuration and power control. However, disturbed conditions of different subframes are different, and receiving nodes or sending nodes are different. If the same management mode is adopted, different requirements of all subframes cannot be met, a performance of the system is influenced, and an efficiency of data transmission cannot be ensured.